JPS5842062A - Quick positive charging of uncharged toner particle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to apparatus and methods for producing positively charged toner compositions. In more detail.

The present invention relates to a method for rapidly charging to a positive polarity uncharged toner particles used to develop negatively charged electrostatic latent images.

Electrostatography, especially xerography, is well known.

It has been described in several prior publications. In these methods, the electrostatic latent image is 1 e.g.
Toner is deposited on the latent image using cascade development as described in US Pat. No. 2,874,063 and US Pat. applied and developed. In some cases, as shown herein, these devices make inverted copies of originals, e.g., from positive originals to negative copies, t
In some cases, it may be desirable to create a copy from a negative manuscript.

In cascade development, a developing material consisting of relatively large carrier particles and finely divided toner particles charged with the opposite polarity to the carrier particles and electrostatically adhered to the surface of the carrier particles forms an electrostatic latent image. It is carried to a supporting surface, rotated once, and cascaded. The charged portion of the surface (generally the photoconductive surface) has a charge of the same polarity as the carrier particles, but the intensity of the charge is usually stronger than that of the carrier particles. Thus, as the developer mixture cascades or rotates over the image bearing surface, toner particles are electrostatically attracted from the carrier particles to the charged portions of the image bearing surface. On the other hand, these toner particles are not electrostatically attracted to the uncharged portions of the image, ie, the pack ground portions, with which they are in contact.

The carrier particles and unused toner particles are recycled.

Magnetic brush development also has almost the same steps as cascade development. However, in magnetic brush development, developer C
Comprising relatively large magnetic carrier particles and finely divided toner particles, the toner particles are electrostatically attached to the surface of the carrier particles and transported by a roller having a magnet to the surface bearing the electrostatic latent image. They differ fundamentally in that they traverse the surface.

To develop a negatively charged electrostatic latent image, the toner and carrier combination is selected such that the toner is triboelectrically positive with respect to the carrier;
To develop a positively charged electrostatic latent image, the toner and carrier combination causes the toner to be triboelectrically negative with respect to the carrier material. In these systems, the triboelectric relationship between toner particles and carrier particles depends on the relative position of the materials in the triboelectric chain. In this series, the materials are arranged in order of increasing ability to carry a positive charge.

Each material is therefore positive with respect to any material subdivided below it and negative with respect to any material above it. An example of this triboelectric series is shown in FIG.

It is also known to use certain charge control agents to impart a positive charge to toner resins. for example.

The use of quaternary ammonium salts as charge control agents in electrostatic toner compositions is disclosed in US Pat. No. 3,893,935. According to the disclosure of this patent, certain
Ammonium salts, when incorporated into toner materials and mixed with a suitable carrier vehicle, are known to provide a relatively uniform and stable net charge of the toner. U.S. Pat. No. 4,079,014 discloses a similar method, except that it uses a different type of charge control agent, namely a diazo type compound. It tends to lose its positive charge. Additionally, certain charge control additives may be immiscible with thermoset resins, making it difficult for the additives to be uniformly dispersed or dissolved in the toner composition. In addition, chemically acting charge control agents can
, adversely affecting equipment parts such as rubber rolls. Therefore, it is desirable to provide a chemically inert toner charging means.

Furthermore, during operation of an electrostatographic imaging device, toner particles are consumed and must be constantly replenished.

This varies depending on factors, including the number of images developed per fraction, the area percentage of the image on the paper, the darkness of the image, the size of the toner particles, etc. Generally, the amount added ranges from about 1 to 20% per minute of the total toner content in the developer. When replenishing the developer, ie, toner plus carrier, used in commercial electrostatographic equipment, the freshly added toner has no charge, ie, is neutral. In order for the toner to properly develop the electrostatic latent image, the newly added toner must be charged to an appropriate level. Charging takes a considerable amount of time, up to about an hour depending on the material used and the meter of the device. These long time delays can have a detrimental effect on the device and result in uncharged, but less charged, toner particles being printed as undesirable packed ground. Additionally, uncharged toner particles commonly accumulate on equipment components and contaminate the equipment, resulting in
Damage the corotron, filter, etc. Such failures are not only costly but also reduce image quality.

Therefore, in order to impart the positive charge of the charged toner particles already present in the developer composition, the newly added uncharged toner particles contained in the positively charged developer composition are
There is a need for a device and method that can positively charge the battery at an appropriate level and magnitude in a short period of time. This is referred to herein as positive charge provision.

The object of the invention is to provide a device and a method that overcome the above-mentioned drawbacks.

A further object of the present invention is to provide a developer composition comprising toner particles and carrier particles, the toner particles being positively charged.

Another object of the present invention is to provide a method for imparting the positive charge of a developer composition containing positively charged toner particles to added, fresh, uncharged toner particles.

Yet another object of the present invention is a method that can be used to develop a negatively charged electrostatic latent image on an imaging surface, the toner composition being stain resistant. flat from the imaging surface without causing or adversely affecting the quality of the resulting image? It is an object of the present invention to provide a method for electrostatically moving a sheet of paper onto a sheet of paper.

These and other objects of the invention are achieved by using matrix materials by which uncharged particles are added to an already charged developer composition. In some cases, it is possible to obtain a method of imparting a positive charge to the uncharged particles in a relatively short period of time.

Charging of new, uncharged toner particles is accomplished by a process referred to herein as positive charging, which continuously brings all particles of the same size to substantially the same level of charge. Thus, in accordance with the present invention, when uncharged toner particles are added to a charged developer, charge is rapidly transferred from the charged initial toner material to the uncharged toner particles, thereby reducing the uncharged state. This ensures that the charge is approximately evenly distributed among all toner particles, including those added to the system. An excess positive charge is then added to the toner particles due to the triboelectric relationship between the toner particles and the carrier particles.

More particularly, the present invention provides a method for rapidly charging toner particles to a positive polarity, the method comprising: adding uncharged toner particles to a charged developer composition comprising carrier particles and positively charged toner particles; Uncharged and charged toner particles have conductive particles, ie, conductive matrix, on their surfaces, and the conductive particles are, for example, carbon black, yttrium oxide-doped zirconium oxide, and the like. Contact the charged toner particles for about 5 seconds to 2 seconds.
During the developer mixing time of minutes, a positive charge is transferred from the conductive particles of the charged toner particles to the conductive particles of the uncharged toner particles, thereby causing both the initially charged toner particles and the added toner particles to have a Positive charge strength at about the same level is about 5 microcoulombs/l to about 50 microcoulombs/? (within the scope of). Conductivity A? Latch, which can be triboelectrically charged to a higher degree than the toner polymer.

According to the method of the present invention, the conductive particles or conductive particles present in the charged toner particles contain the majority (a factor of 50 or more) of the positive charge imparted to the toner particles from the carrier particles. The carrier particles are triboelectrically more positive than the toner resin. What is important is that the conductive particles or patches contained in the toner surface are brought into contact with uncharged toner particles, whereby the positive charge contained in the patches is transferred by conduction to the uncharged particles. However, it is not necessary that all conductive particles on the toner surface contact uncharged toner particles. The new uncharged toner particles thus added are rapidly charged to the appropriate level by the method of the present invention, allowing them to be used for image development. The toner particles contained in the developer composition are then further triboelectrically charged by the carrier particles present in the developer composition.゛Hereinafter, the present invention will be explained with reference to the accompanying drawings.

FIG. 1 shows the charge distribution of toner particles, which is a plot of the number of particles having a given charge value for toner particles in a particular narrow size range. Such a distribution map is disclosed, for example, in pending U.S. Patent Application No. 186,981 (filed September 20, 1980).
obtained by measuring using a charge spectrograph such as the one described in . The charge contained in the toner particles of a given developer generally varies considerably depending on the size of the toner particles. Therefore, whether the charges contained in toner particles are equal means whether the charges are equal within any given particle size range.

With respect to FIG. 1, FIG. 1A shows the properties of a developer composition having features of the present invention, while the developer shown in FIG. 1B exhibits features of the present invention. . That is, in FIGS. 1A and 1B, the toner charge distribution initially marked with l indicates that the toner charge is in an equilibrium state (it will not be charged even if it is further mixed) after being tampled in a roll mill for about 1 hour and mixed well. (The toner charge distribution marked 115 seconds is for the developer composition achieved by adding the uncharged toner to the well-mixed initial I developer and then mixing for an additional 15 seconds. This is the developer obtained for 2 minutes, 5 minutes, etc.

The toner charge distributions shown as and 15 minutes represent fresh toner added to well-mixed developer and then mixed for corresponding lengths of time.

Regarding FIG. 1A, the toner particles of the first well-mixed developer 1 do not contain conductive particles and have a distribution represented by a certain average charge Q, which is close to zero as is clear from the graph. There are no charged particles.

If new toner particles containing particles without conductive surfaces are added to this developer and mixed for 15 seconds, at the charge distribution marked 15 seconds, the added toner particles will initially drop to zero. It has a charge close to 2. This is then mixed and the added toner particles 2 acquire a high charge level as shown in the remaining figures of FIG. 1A. After 15 minutes of mixing, the charge on the toner particles collects into a single peak and the developer reaches a new, well-mixed specific state of new toner concentration level, with no toner particles near zero charge. However, if the mixing time is short, two peaks remain and a significant number of toner particles have no or little charge. Does the initial particle and the added uncharged toner form a single peak (a peak that does not become narrower with further mixing)? The time required for this to occur is the charging and mixing time of the developer composition. In the present example, 15 minutes are required to obtain adequate charge mixing, but of course this time may vary over a fairly large range, perhaps from 10 minutes to an hour, and such phenomena may occur as discussed herein. Undesirable.

FIG. 1B shows the properties of a developer composition that characterizes the present invention. The developer composition of FIG. 1B includes conductive surface particles in its toner; in this example, the developer composition of FIG. This developer composition, as described in Example 3, includes toner particles,
Charge mixing occurs within about 15 seconds according to the method of the present invention, as illustrated.

The single peak that occurred after a mixing time of 15 seconds indicates rapid charge transfer from charged to uncharged toner particles. Therefore, the developer composition is ready for use in developing electrostatic latent images. Further, as shown in FIG. 18, the toner particles shift to a high charge with a single peak after 2 minutes and 5 minutes. However, it is noteworthy that even after 15 seconds there are no particles with low or zero charge.

In FIG. 2, positively charged toner particles 3 and uncharged toner particles 4 are shown.
, a conductive particle or conductive patch 5, a positive Mi charge 6 is shown whose positive charge, as indicated by arrow 7, transfers to the conductive particle 8 of the uncharged toner particle, which increases the conductivity of the charged toner particle. This results from contact between the particles and the conductive particles of the uncharged toner particles. Therefore, the charge moves from the conductive patch 5 to the conductive patch 8 which has no charge. In this way, since the charged toner particles have a high potential, the charged toner particles and the uncharged toner particles come into contact and the positive charge mainly present in the conductive particles of the charged toner particles is transferred to the uncharged toner particles. . When these particles are mixed together, it is not necessary to have a portion of the solder, ie, relatively few conductive particles, which come into contact and create approximately the same electrical potential and thereby all toner particles. The same charge is generated.

Examples of particles that are useful in the present invention and have a conductive surface include conductive resins (the particles can also be in the form of a matrix of toner particles), triboelectric particles with respect to the toner resin. Contains materials that are positive. That is, the conductive particles have a resistivity of 109 ohms/cm (semiconductor) to 10-' ohms/On O and are made of a material that can be made submicron in size.

Specific examples of particles with electrically conductive surfaces include metals such as gold or copper, silicon, semiconductor materials such as rumanium or black, magnetite, reduced titanium oxide, doped antimony oxide. Conductive gold oxides such as aluminum, reduced zirconium oxide, conductive organic polymers such as reduced acetylene, and metalloids such as kagen, be. An example of a preferred material used in the method of the invention is Regal 330.
) car yW7p, rack, and rapen 420 (Ra
ven 420) Kerr M:yf-ytsuk, there are solid solutions of yttrium oxide and zorconium oxide, in particular solid solutions of 12 percent yttrium oxide and zirconium oxide (ZYP powder), these materials are combined with common resins - especially Styrene and vinyl chloride resins can be positively charged. In general, any conductive material that can be made into particles of about 1 micron or less may be used, but from a practical standpoint, these materials must be atmospherically stable and economical.

Furthermore, in order for the conductive particles to dominate triboelectric charging, particular conductive particles are well suited for particular carrier coating compositions and particular toner polymers. for example,
When the conductive material is mixed with the toner resin 1 and the resulting composition is compounded according to known methods, it is important that the conductive material has a stronger positive charge than the toner polymer in the triboelectric series.

This will be further explained clearly with reference to FIG.

Figure 3 shows the triboelectrification series of various materials according to the work function (work function, unit /
fi volts). In this case, PMMA is polymethyl methacrylate and KELF-800 is a copolymer of chlorotrifluoroethylene and vinylidene fluoride, listed with other materials as shown. For example, what is the work function for polyvinylpyridine? A=)? 3, 4, one-way valve oxidation carbon black, polyester, and gold work function Fi4
, 3, and the work function of highly oxidized carbon black and polystyrene is 4.8. What is the work function for the conductor? Ruto is Revlew of 5cient 1c
Instruments, VOt, 3, page
367, (1952) K. 367, (1952).
) is generally determined by This disclosure will also be referred to in the present invention. On the other hand, the value of the effective work function of a polymer can be obtained by measuring the charging characteristics when the polymer comes into contact with a conductor of known work function.

Thus, once the effective work function of a polymer is determined, whether a material can be used as a conductive patch that imparts a positive charge when used with a given polymer depends on the material's contact potential ( This is usually determined by measuring the work function of a gold or other suitable standard material (usually determined as a value for a known standard) and comparing that value with the work function of a polymer. The polymer is polystyrene (work function = 4
．． 8V), highly oxidized carbon black would probably not be a suitable positive charge imparting agent. The reason is that highly oxidized carbon blacks have approximately the same work function. However, non-oxidized carbon blacks with lower work functions (high contact voltages) are well suited. Polyester resin has positive charging power - What is ZENBLACK? Since their work functions are on the same level, these carbon blacks are not suitable as agents for imparting positive charges to polyester resins, and oxidized carbon blacks, which are strongly negative, are even less suitable. However, from this point of view, a strongly positive Z Y P y4'Uda is preferred.

In order to cause a strong banding of the conductive particles, i.e. the conductive colorant, the surfaces of the toner polymer resin and the carrier are selected to be materials in close proximity from the triboelectric series arrangement, while
The conductive particles are selected from materials that are significantly more positive than the toner polymer and carrier. The conductive particles must be more triboelectrically positive than the toner resin, and the resin must be capable of being at least as positively charged as the carrier surface. Thus, the materials are precisely selected to obtain the desired charge application pattern and to obtain the desired charge level. Examples 3.4 and 5 show that the toner resin is a positive car? When mixed with black colorants and carrier polymers (all of which impart a charge), the charge levels of these colorants and carriers also become progressively more strongly positive, while the toner resin mixture gradually becomes more positive. It shows that it is strongly positive.

The positive charge contained in toner particles is normally distributed evenly between the toner polymer and the conductive material, or colorant; however, for best results, the conductive material, or colorant, must dominate the charge. In other words, it is desirable that this non-touch contains most of the charge (for example, about 50 to over 90 parts of the positive charge),
This allows the charged toner particles to provide sufficient charge to the uncharged toner particles.

Generally, both the conductive particles, the colorant and the toner resin, are physically and electrically available at the surface of the polymer mixture. When both are available, charge distribution is determined by the relative order of the triboelectric series. To impart a positive charge, the conductive colorant must be sufficiently larger than the toner polymer in the triboelectric series to dominate the charge, and sufficiently far away from the carrier surface in the triboelectric series to generate the desired charge level. There must be. The amount of conductive particles present on the surface of the toker particles is of some importance. However, generally only an amount sufficient to achieve the objectives of the invention is needed. In general, it is neither necessary nor desirable that the surface of a toner particle be completely covered with conductive particles, but rather that the particles form a series of patched (i.e., interspersed) areas. is present on each resin toner particle, thereby leaving one area of the toner resin free of conductive particles such that the entire surface of the toner particle is insulating and non-conductive. Approximately 1 part of the surface of the toner particle
The 0 coefficient may include conductive particles, but the toner resin particles may also include particles having a small amount of conductive surface, such as about 1 coefficient. That is, A'j'? Although a range of conductive temperatures is effective, it does not actually form a conductive surface, although it comes close to providing one. More specifically, each toner particle includes particles having about 5 to 15 square conductive surfaces. The thickness of the conductive particles included in the toner particles ranges from about 10 millimicrons to about 1 micron, preferably from about 25 millimicrons to about 0.5 microns. However, this thickness is not a critical factor unless the electrical properties of the device are adversely affected.

In negatively charged toners, highly oxidized casen black colorants are often used with resins (eg, polyester or styrene normal butyl methacrylate). In this case, the colorant is lower in the triboelectric series than the resin polymer. Also, oxidized car? Black is usually poorly dispersed in the resins mentioned above. This carton black therefore forms large chunks that are exposed when the toner is rubbed together.

Due to the exposure of the oxidized carbon black and its position at the end of the triboelectric series, the carbon black dominates the charging. However, when the toner is made positive by using a carrier polymer with a very low triboelectric charge series, contact charging interactions tend to charge the toner polymer rather than the car black. This is because in this case the toner polymer is at the end of the triboelectric series among the carrier, toner colorant and toner polymer. When mixed vigorously for 10 minutes, this imaging agent composition becomes positively charged, but does not impart a charge (see Example 1).

The conductive particles adhere to the toner particles and the insulator is embedded in its surface. Many methods of attachment and embedding are known. For example, conductive particles are mixed with a toner polymer,
The resulting composition is rubbed together to form toner particles. In this case, the conductive particles, or colorants, must be electrically useful near the surface of the toner resin. The reason for this is that the mixing process often covers the colorant with a fairly thick layer of polymer, making contact with the carrier or other toner particles impossible. Low dispersion must be carefully created so that some colorant is exposed by rubbing. Nevertheless, the polymer and the conductive two particles compete to obtain charge from the carriers.

Therefore, the conductive particles must be more triboelectrically positive than the toner polymer.

Another method of deposition is to coat the surface of the toner particles with a conductive material by mechanical mixing and then exposure to high temperatures in an air column. This method fixes the conductive material to the surface of the toner particles.

The level of positive charge magnitude achieved by uncharged toner particles added to the system and charged toner particles already present in the system ranges from about 5 microcoulombs/p to 5 microcoulombs/p.
0 microcoulomb/y-(uc/il-), preferably from about 10 uc/f to 50
uc/f. For proper operation of the system, the level of charge magnitude must be at the bottom about 5 uc/f.
The unused charged toner particles already present in the system and contained in the carrier particles are typically about 10 u
It has a charge ranging from c/f to about 30 uc/jF. When new uncharged toner material is added to the charged developer composition, toner particles of each size acquire the same level of charge. Thus, the already charged toner particles will have a slightly lower charge level, and each toner particle will impart a charge to a new uncharged toner particle added to the system. Therefore, this results in a transfer of charge between the charged toner particles present in the system and the uncharged toner particles added to the system. Although the charging level is significantly reduced, this does not have a detrimental effect on the imaging device. This is because all toner particles have a sufficient charge, and these particles are electrically controlled and attracted to the carrier, that is, a static image, thereby developing the latent image. Further charge is picked up from the carrier particles by the frictional electrical relationship between the carrier particles. This triboelectric relationship has already been discussed. As a result of the charging and triboelectric relationship between the toner and carrier particles, the toner particles maintain their charge level.

Developer compositions exhibiting features of the present invention charge rapidly by transfer of charge between previously charged toner particles and newly added uncharged toner particles, such that the newly added uncharged toner is a carrier. Rather faster than electrification by contact with a surface. Examples 2 and 5 show the differences in the mixed charging modes.

Many different materials can be used as toner resins, and the objectives of the present invention can be achieved through the use of these resins. However, typical resins include polyamides, epoxies, polyurethanes, vinyl resins, and polyesters, especially those made from dicarboxylic acids and diols, including diphenols. Any suitable vinyl resin can be used, including homoprimers or copolymers of two or more peenyl monomers.

Typical vinyl monomer units include styrene, vinyl styrene, vinyl naphthalene, ethylenically unsaturated monoolefins (e.g., ethylene, clopylene, butylene, isobutylene); vinyl halides (e.g., vinyl chloride, vinyl chloride, etc.); , vinyl bromide, vinyl fluoride), vinyl esters (e.g. vinyl acetate, vinyl zorobio*-), vinyl benzoate, vinyl butyrate), etc.: esters of alpha methylene aliphatic monocarboxylic acids (e.g. methyl Acrylate, ethyl acrylate 1, -t, normal butyrahfurylate, inbutyl acrylate, dodecyl acrylate, normal oxyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methialphachloroacrylate, methyl methacrylate, ethyl methacrylate, butyl rylonitrile, acrylamine゛Do,
Vinyl ester (e.g. Eva, vinyl methyl ester,
vinyl isobutyl ester, vinyl ethyl ester), etc.; vinyl ketones (e.g., vinyl methyl ketone, vinyl hexyl ketone, methyl isozolobenyl ketone 7, etc.)
Vinylidene/lokene compounds (eg, vinylidene chloride, vinylidene chlorofluoride, etc.); and normal vinyl indole, normal vinyl pyrrolidine, etc.; and mixtures thereof.

In general, toner resins containing a relatively high percentage of styrene are preferred. The styrene resin used may be a homopolymer of styrene, consisting of a homopolymer of styrene or a copolymer of styrene with other monopolymer groups. A single unit of any of the representative monomers described above may be copolymerized with styrene by addition polymerization. Styrenic resins may also be formed by polymerization of styrene monomers with mixtures of two or more unsaturated monomer materials. Polymerization techniques used include known polymerization techniques, such as There are radical polymerization, anionic polymerization and cationic polymerization methods. Any of these vinyl resins may be mixed with one or more resins if desired and preferably have good triboelectric properties. However, non-vinyl thermosetting resins can also be used, including resin-modified phenol-formaldehyde resins, oil-modified epoxy resins, etc. , polyurethane resin,
Includes cellulose resins, polyester resins and mixtures thereof.

The carrier particles can be any carrier material that can triboelectrically acquire a charge of opposite polarity to the toner particles. In one embodiment of the invention, the carrier particles are of negative polarity.

The toner particles therefore adhere around the carrier particles. Thus, the carrier particles can be selected in such a way that the toner particles can obtain positive polarity, and include, for example, sodium chloride, ammonium chloride,
Potassium ammonium chloride, Rochelle salt, sodium nitrate, ammonium nitrate, potassium chlorate, granular zircon, granular silicon, methyl methacrylate, glass,
Includes steel, nickel, ferrite iron, silicon dioxide, etc. In this case, metal carriers, especially magnetic carriers, are preferred. This turnip may or may not have a coating. Generally, the coating is made of polyfluoride resin 1
．． In particular, other negatively charged resins (e.g., polystyrene, halokene containing ethylene), etc. are used. Many representative carriers that can be used include U.S. Pat.
, No. 441, No. 2.638.522, No. 5.618.
No. 522, No. 3,591,503.

Also, U.S. Patent Nos. 3.847,604 and 3.767
．． As described in Part No. 59=Tsugarube lJ=
(berrV) carriers can be used; these carriers are modular carrier particles of nickel characterized by an undulating surface giving the particles a relatively large outer surface. The diameter of the coating carrier material is about 50 microns to about 100 microns, so the carrier has sufficient density and inertia to prevent the particles from adhering to the electrostatic latent image during the development process.

The carrier can be used with the toner composition in any suitable combination. However, the first part
When used, best results are obtained when used with about 10 to 20 parts by weight of carrier particles.

The toner particle compositions of the present invention can be used to develop electrostatic latent images on any suitable electrostatic surface capable of retaining a charge, including conventional photoconductors.

However, the toners of the present invention are best utilized in @ conditions where the photoreceptor is negatively charged, and this development typically occurs on organophotoreceptors. Examples of such photoreceptors include polyvinylcarbazole, 4-dimethylaminopentuline, penzuhi Pazide; 2-benzylidine-amino-carbazole,
4-dimethylamine-pencillinone, benzhydrazide; 2-pendylisone-aminocarbazole, polyvinylcar-bromoaniline: 2,4-diphenylene quinazoline: 1', 2, 4-) riazine: 1,5-
Diphenyl-3-methylpyrazoline, 2-(4''-'dimethyl-aminophenyl)-benzoxazole: 3-
Amino-carbazole: folivinylcarpazole trinitrofluorenone charge transfer complex, phthalocyanine,
There are layered photoresponsive devices that include charge emission, charge generation layers, and the like.

It should be noted that the following examples are given to further clarify the features of the invention, and that these examples are intended to be illustrative and not to limit the scope of the invention. Parts and percentages are by weight unless otherwise indicated.

Example 1 - 95% by weight epoxy resin Epon 1004 (this is a polymer commercially available from 5hell○11).

) and 5 weight carbon black Raven 1020
(This is Columblan Chemical Co.
It is commercially available from mpany. ) were melt-mixed and then this mixture was rubbed to prepare a toner composition. Next, this toner composition is prepared using halodanized polymer FP.
It was mixed with a carrier consisting of a ferrite core coated with C461. This FPC461 is polyvinyl fluoride yf! Firestone Plastl in 9-r-
cs Co.

It is commercially available from. The mixing time of the developer composition was 10 minutes as measured by charge spectrograph, which indicates that no charge deposition occurred. ! Referring to FIG. 3, the toner polymer of this example, the epoxy resin, is more triboelectrically positive than both the carrier coating and the conductive carbon black (Raven 1020). Therefore, the carton black does not meet the criteria of the present invention that the carton black must be more triboelectrically positive than the toner I remer to obtain charging.

Example 2 A steel carrier core was coated with a methyl terpolymer. This terpolymer consists of a polymer of 80.9% Fi methyl methacrylate, 14.3% styrene, and 4.8 qb vinyltriethoxysilane. For this carrier, the toner of Example 1 becomes triboelectrically negative.

The carton black (Raven 1020) is more strongly negative than the toner resin (see Figure 6), and the carton black receives most of the charge, resulting in a negative rather than a positive charge. Ta. The charge mixing time of this developer is 15 seconds as measured by charge chromatography. This rapid mixing time indicates that negative charging is occurring.

When this developer composition was made from fresh toner and fresh carrier, a mixing time of about 15 minutes was assured for the charge to reach equilibrium. This increases the 15 seconds it takes to add and charge the toner to the already mixed developer; thus, the new toner particles are slowly charged by the carrier particles.

Example 3 Toner is 90% by weight halodanized polymer FPC47
1, (This is Flrestone Plastlcs
There are fluoropolymer chains commercially available from. ) and 10
Weight% Elzu tax 13 (Cabot Corp
A commercially available carton black (commercially available from Orat Ion) was mixed and the mixture was combined to prepare the mixture. This toner was mixed with the FPC461 coated carrier of Example 1 and a similar mixing experiment was performed. FPC471 polymer and FPC461f! The triboelectric properties of the rimers are the same. (See Figure 3) Elftex 8, on the other hand, is located higher in the triboelectrification series than the two materials, namely FPC471 and FPC461, and this carbon black can dominate the charging and therefore meets the criteria of the present invention. be satisfied.

The mixing time measured for this developer composition was 15 seconds, indicating that positive charging occurred, and the toner particles were 21 microcoulombs/? It is.

Example 4 Toner is 751FPC471, 15%'Epon100
4 and 10% Elftex f3 were mixed and adjusted by grinding. When mixed with the carrier of Example 6, the mixing time was 15 seconds, indicating that the resin composition was more negative than the conductive Karsenbraz Elftex 8, which also had a positive charge. Indicates that a grant is occurring.

Example 5 Toner is 60 FPC471, 30 [p□n
It was prepared and tested according to the method of Example 3, except that it consisted of 1004 and 10% El tex 8 strength. This toner is triboelectrically positive, with a mixing time of 15 seconds, indicating that charging forces are occurring.

The developer composition was prepared in combination with toner and fresh carrier and then mixed on a roll mill for 05 minutes, and the charge level of the developer composition reached 90 parts of the equilibrium value.

The negative mixing time/li of the toner composition of this example and the methyl terpolymer coating carrier is 8 minutes.

Example 6 Toner is Po1lollte (This is Goody
It is a styrene-butanoene copolymer commercially available from earCtvemlcal Company. )
and Regal 330 (Cabot Corporation
It was prepared by mixing Kagen Black (commercially available from ION). This toner ij Aerosil
(This is a finely divided silica powder commercially available from Da'gussa Corporation.). The resulting material was passed through a heated air column to settle and blow out any remaining loose material. The photograph shows the toner surface uniformly covered with aero eyes using rsEM (scanning electron microscopy). Therefore, conductive material is likely to exist on its surface. This toner is mixed in the same manner as in Example 1 with the same carrier as in Example 1 for 51 minutes.

Example 7 Raven 420 (This is Columbian C
The carton black is commercially available from Chemical Compan, Y. ) were prepared according to Example 6 except that they were mated together on the surface of Aerosil. This surface contains conductive particles, cardan black, which is more positive than Aerosll. The mixing time of the carrier of Example 1 and this toner was 15 seconds, indicating that the positive charge is impeded.

Example 8 The toner is a ZYP powder (which is a solid solution of zirconium oxide and yttrium oxide, commercially available from ZlrCar, Inc.) and Raven
420 car? Prepared according to Example 7 except that black was substituted. This ZYP powder has electrical conductivity, and Aerost+ is also strongly positive. The mixing time of this toner with the carrier of Example 1 was 1 minute, indicating that positive charging occurred.

Example 9 A toner was prepared according to Example 5, except that a toner polyester resin consisting of the reaction product of bisphenol A1 propylene glycol and fumaric acid was substituted for PI lol Its Tree C. The surface of the toner is Asro
It is covered with sll and tends to become oval when heated.

The photograph (SEM) shows the toner surface uniformly covered with Aerosll. Therefore, no conductive material is present on its surface. The toner of this example required 15 minutes of mixing time with the carrier of Example 1, and no charge was generated.
It is shown that.

Example 10 The toner is Raven 420 and Aeros
Prepared according to Example 6 except rubbing onto the surface of the l l. The toner of this example required 15 seconds of mixing time with the carrier of Example 1, indicating that charge deposition occurred.

Example 11 A toner was prepared according to Example 9 except that the ZYP powder was rubbed onto the surface of the Aerosll at the same time.

The toner of this example required 1 minute of mixing time with the carrier of Example 1, indicating that positive frost "loading" occurred.

Other modifications of the invention may be made by those skilled in the art based on the disclosure herein and are intended to be within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1, consisting of FIGS. 1A and 1B, generally represents the distribution of the number of toner particles with a given charge strength for toner particles of uniform size. FIG. 2 shows charged and uncharged toner particles having conductivity and t4 contained in the charged toner particles.
This figure shows the movement of positive charges from the toner particles to the uncharged toner particles. FIG. 3 is a diagram showing a triboelectrification series. Explanation of symbols 3...Positively charged toner particles, 4...Uncharged toner particles, 5...Conductive particles, 6...Positively charged. FIG /a /%/b FI6.2 (Upper rate score F/6.3!YP Pacta ゛2 PMM &, Evo 1 pin 14m, 7 doo Lutao: Rin□shioxidation car tree'〉Prack No. Continued on page 10 Inventor: Lovanid J.A. Gruber, 40 Rosewood Drive, Bitzford, New York, United States 14534

Claims (9)

[Claims] (1) A method for rapidly charging uncharged toner particles to a positive polarity, in which charged and uncharged toner particles have conductive particles or conductive patches on their surfaces. In a system in which the conductive patch is capable of positively tribocharging to a higher degree than the toner polymer, uncharged toner particles are added to a positively charged developer composition comprising carrier particles and toner particles; contacting one particle with an uncharged toner particle to transfer a positive charge from the conductive particles of the charged toner particle to the conductive particles of the uncharged toner particle for a period of about 5 seconds to about 2 minutes, thereby causing the first charged toner particle to from about 5 microcoulombs/2 to about 50 microcoulombs/? for both particles and added toner particles. said method, characterized in that said method produces substantially the same level of positive charge strength. (2) The method according to item 1, wherein the conductive particles are selected from Karzan black, zirconium oxide doped with yttrium oxide, or magnetite. (3) The method according to item 1, wherein the toner resin is comprised of a stilbutyl methacrylate copolymer resin or a styrene butanoene resin. (4) The styrene butyl methacrylate resin is 6
The styrene-normal/butylmethacrylate IJ rate contains 5% by weight of styrene and 35% by weight of normalbutylmethacrylate, and 9% by weight of styrene-butadiene resin.
4. A method according to claim 3, characterized in that it contains 0% by weight styrene and 10% by weight butadiene. (5) the uncharged toner particles acquire a positive charge between about 5 seconds and about 1 minute, and the charge is about 1 Ω microcoulomb/l;
2. A method according to claim 1, characterized in that the temperature is about 30 microcroms/2. (6) The toner resin surface is about 5% to about 15% by weight.
The method according to Patent No. 1, characterized in that it contains conductive particles of t% by weight. (7) The conductive particles are about 100 m to about 10 m
2. The method of claim 1, wherein the particles have a resistivity in the range of 0-σ and a size in the range of about 0.05 microns to about 3 microns. (8) The conductive particles have mostly positive charges. 2. The method of claim 1, wherein the conductive particles are more triboelectrically positive than the toner resin polymer, and the toner resin polymer is more triboelectrically positive than the carrier surface. (9) the conductive particles have a predominately positive charge, the particles being triboelectrically more positive than the carrier surface, and the toner resin polymer being triboelectrically neutral with respect to the carrier surface; The method according to item 1, characterized in that: